Treating solids with liquid



June 11, 1935. P. LA F. MAGILL v 5 3 TREATING soups WITH LIQUID Filed Oct. 17, 1932 side ofcon fa/her INVENTOR; Pau/ M/Fofle Mag/W BY A TTORNEY' Patented June 11, 1935 TREATING soups WITH LIQUID Paul La ore Magi'lr'lnia a'ra Falls, n, as-

signor to E. I. du Pont de Nemours accompany, -Inc., Wilmington,;Del., acorporation of Delae ware Application October '17, 1932, Serial No. 638,183

9 Claims. (ores-151),

This invention relates to a process for heat ing a solid material with a liquid, jthe generation of hydrocyanic acid gas, and more particularly to the generation of hydrocyanic acid from solid cyanide substances by reactionwith water;

f It has been proposed to generate hydrocyanic acid by reacting water with a mixture of alkali metal cyanide and a salt having a base which forms an unstable cyanide and in addition, when desired,a salt having a high heat of hydration.

In addition to this method of generating hydro-' cyanic acid, unstable cyanides;forfinstance an alkaline earth metal cyanide such as calcium cyanide, may be reacted with water to "generate hydrocyanic acid. v In order to utilize these 'meth-' ods of generating hydrocyanic acid for fumiga tion purposes, the solid pulverantbyanide'ma-l terial is placed in a suitable container and water is addedthereto atthe point "of use. A disad-f vantage in this operation is that the water often does not uniformly penetrate the cyanide material and consequently does not reactwith' all the cyanide. Furthermore, theusual method of applying water" to 'pulverant masses in this man surface. In addition to the resistance to-the es;

(1 cape of the hydrocyanic or other gases,jthere is increased resistance to the penetration of the water downward. Insomecases this" resistance is so serious thatthe reaction material maybecome caked and the water will not reach the '1 lower layersat all. 1 This results in a waste of fumigating material, inefiectiveconcentration of the hydrocyanic acid, and the remaining residue, which "contains relatively large amounts of reacted cyanide material, is hazardous tolhandle. An object of this invention is totreat a solid materialwith a liquid in such manner'that the ,liquid is quickly" and uniformly distributed throughout the solid material. A further object is to providea method whereby solid cyanide r* materials may be reacted with water to generate hydrocyanic acid injsuch manner that the added water will be uniformly distributed throughout thefmass of cyanide material, and the gases will escape freely;- Further-objects will from the following description.

Theseobjects are accomplished, according to my invention, by introducing the liquidiinsuch manner that it penetrates upwardly. in a sub stantially uniform manner throughout'the mass be apparent of. solid material; While, fromisome methods of:

introduction of the liquid some of the penetration may be from one side as, well as from the bottom, in general the liquid introduction is in such manner. as to leave at least a portion of the surface and contiguous portions below the surfacedry as long as there is any appreciable amount of;material under the surface not yet, contacted with water. There are several ways of securing this pence" tration of the liquid upward through the mass to be treated such as for example, supporting the mass on aperforated 'plate over a water chamber and supplyingthe liquid to this chamber through an external tube connection; other special apparatus could thusbe constructed on the same principle. Such methods, however, are unsatisfactory in that the amount of water in the reservoir below the false bottom is never used and would aiford a problem in residue disposal;

chamber. i i

I have-discovered that if "a layer of pulverant material is'spread on a foraminous or. perforated. sheet in the nature of a movable false bottom placed directly on the bottom of a container, that the reaction water can be introduced beneath such sheet' and will tend to raise it and will pass through thesheet and thereafterpenetrates uniformly upwards through the solid material. By this method it is unnecessary to add more water than I is required to react with. the. solid material.

\ My invention is not to be confused with theex pedients mentioned above in which a chamber is provided beneath a false perforated bottom in the vessel. Such structures are undesirable, since they leave an excess of liquid in the chamber which cannotv penetrate upwards, whereasiaccording to my invention, the material is placed on its pervious sheet directly on the bottom of the container and will therefore take up substantially allof the liquid provided. The amount of liquid added having been previously adjusted to the requirements of theimasasubstantially all of the solidri's contacted with liquid, and at the same timeexcess water and the resulting pasty mass may be avoided.

I fOne methodof carrying out my inventioncom prises placing a layer of pulverant, granularjor porous solid material'on aforaminous or perfo rated sheet and introducing the liquid beneath, said sheet. The liquid flows through the sheet and penetrates uniformly throughout thelayer of solid material; The sheet-may be of any material which is pervious to water,for'instanceperforated metal or wooden-plates, wirescreen or coarsely alsoi..solid material would enter and clog this ES} PATENT OFFICE woven cloth. I prefer to use a coarsely woven cotton cloth, for instance the type known as cheesecloth. According to my preferred method, as illustrated in the appended drawing, a piece of cheesecloth is placed in the bottom of a suitable container and a layer of pulverant solid material is placed thereon to a suitable depth, for instance several inches. Water is then introduced below the surface of the cloth and caused to flow therethrough into the body of the solid material. A convenient method of applying the water is to cause it to flow down one side of the interior container wall, preferably in a narrow stream. The down-flowing stream of water penetrates the solid material adjacent to the container area covered by the cloth. The water flowing be' neath the cloth is quickly conducted therethrough and penetrates upwardly through the solid material in a uniform manner. When a water-pervious sheet which lacks the flexibility and/or buoy ancy of cloth is used, the water must be introduced thereunder by other means which willbe apparent to one skilled in mechanical principles.

The following example illustrates the use of my invention for the generation of hydrocyanic acid by treating a solid cyanide material with water.

Example I A circular piece of cotton cheesecloth was placed" so as to entirely cover the bottom of a cylindrical galvanized iron container having a diameter of about 20 inches. Twenty-five pounds of a pulverantfumigant mixture, containing about 30% by weight of sodium cyanide and about by material is spread on a foraminous or perforated weight of dehydrated aluminum sulfate, was placed upon the cloth making acontinuous layer about 2 or 3 inches in thickness, entirely covering the cloth.

About twenty-five pounds of water was added to the salt by pouring the water down one side of the interior of the container. The water flowed through the salt layer adjacent the side wall at the point of contact and penetrated below the cheesecloth. Thence, it flowed upwards through the cheesecloth and penetrated the mass of salt; a small portion of the water was of course absorbed from the side at'the point of contact. After the evolution of hydrocyanic acid was complete, the residue consisted of a spongy, friable mass of practically dry salts. Upon analysis of the residue it was found that 92.58% of the cyanide in the original mixture had reacted with the water.

' Example II center thereof. In this case, analysis of the residue showed that 92.7% of the cyanide in the original mixture had reacted with the water.

Examination of the residue indicated that water of it.

Example III A two-inch layer of the aluminum sulfate-cyanide mixture, described in Example I, was placed in the bottom of a cylindrical container and water was added thereto by flowing it down one side of the interior wall without using the foraminous sheet. This was repeated a large number of times; in a group of thirteen runs the average amount of cyanide which reacted was 83.9% of that in the original mixture. In some of the runs the amount of cyanide reacted was as low as 61.0%.

Various methods of carrying out my invention will be apparent to those skilled in the handling of materials. For instance, the solid material may be sup orted at the bottom of a container on a pervious or perforated sheet and water may be introduced under this said sheet, for instance by means of suitablepipe connections. Another possible modification of my invention comprises 7 placing the solid material in a shallow container of pervious material and loweringit into asuitable vessel which contains the required amount of water to be absorbed by or reacted with the solid material.

It will be understood that my invention islnotrestricted to the reaction of water with cyanide mixtures to generate hydrocyanic acid; but also is applicable to other reactions between liquid and solid materials. It also may be used to saturate solid materials with a liquid. p

The chief advantage of my-invention is that it provides a means for obtaining rapid and uniform distribution of a liquid through a mass of solid material. For example, in the use of my invention for generating hydrocyanic acid, this uniform distribution of water throughout the mass of cyanide mixture insures completereaction of the cyanide. This results in asuitable yield of hydrocyanic acid gas and prevents wastage of materials. Moreover, by insuring complete reaction of the cyanide, my invention obviatesthe hazards incident to removing and disposing of the reaction residues. ried out according to: my preferred method it is simple in operation and does not require expensive apparatus or materials. A further advan-' tage of the invention is that it may be used to, aid in the removal of reaction residue from the For instance, if a shallow container comprising introducing water overan extendedarea on the under side of a movable false bottom pervious to water and supporting a layer of solid material capable of reacting with water to generate hydrocyanic acid in such manner that the water is substantially entirely absorbed by said solid material. 7

2. A process for generating hydrocyanic acid comprising placing a layer of solid material capable of reacting with water'to' generate hydro cyanic acid on a sheet of materialpervious to water and applying water to the under side of said'sheet in such manner that the water is substantially entirely absorbed by said solid material.

3. A process for generating hydrocyanic acid comprising placing a layer of a; pulverant mixture .When the invention is car-;

of alkali metal cyanide and anhydrous aluminum sulfate on a. sheet of foraminous material and".

applying water to under side of said foraminous' material in such manner that the Water is substantially entirely absorbed by said solid material.

4. A process for generating hydrocyanic acid comprising placing a layerof a pulverant mixture of sodium cyanide and anhydrous aluminum sulfate on a sheet of cotton cloth and applying Water to under side of said cloth in such manner that the Water is substantially entirely absorbed by said solid material. i

5. A process for generating hydrocyanic acid comprising placing a layer of solid material capable of reacting with water to generate hydrocyanic acid upon a sheet of material pervious to water in a container and introducing water beneath said sheet. t

6. A process for generating hydrocyanic acid comprising placing a layer of a pulverant mixture of alkali metalcyanide and anhydrous aluminum sulfate upon a sheet of foraminous material in a container and introducing water beneath said sheet. i

'7. A process for generating hydrocyanic acid comprising placing a layer of a pulverant mixture of sodium cyanide and anhydrous aluminum sulfate upon a sheet of cotton cloth in a container andintroducing water'beneath said sheet. 8. A process for generating hydrocyanic acid comprising placing a layer of a solid material capable of reacting with water to generate hy- 1 9. A process for generating hydrocyanic acid 15 comprisingplacing a layer of a puIVerant mixture of alkali metal cyanide'and anhydrous aluminum sulfate upon a sheet of cotton cloth in a container and introducing water beneath said sheet by flowing the water down the container 2 wall.

PAUL LAFRONE MAGILL.

10 drocyanic acid upon a sheetof foraminous ma- 

